Optical information reproducing method, optical information reproducing apparatus, and optical information recording medium

Abstract

An optical information reproducing method includes: obtaining information about a wavelength of a reference beam at recording time from a recording medium which stores main information recorded as a pattern corresponding to interference between an information beam and the reference beam and information about the wavelength of the reference beam at the recording time; determining an aiming temperature, which is a temperature of the recording medium suited to reproduce the pattern; determining an aiming incident angle, which is an incident angle of the reference beam at the reproducing time suited to reproduce the pattern; controlling the temperature of the recording medium so that the temperature of the recording medium is generally equal to the aiming temperature; and controlling the incident angle of the reference beam at the reproducing time so that the incident angle of the reference beam at the reproducing time is generally equal to the aiming incident angle.

1 . An optical information reproducing method comprising:
 obtaining information about a wavelength of a reference beam at recording time from a recording medium which stores main information recorded as a pattern corresponding to interference between an information beam and the reference beam and information about the wavelength of the reference beam at the recording time;   determining an aiming temperature, which is a temperature of the recording medium suited to reproduce the pattern, on the basis of difference between the wavelength of the reference beam at the recording time and a wavelength of a reference beam at reproducing time;   determining an aiming incident angle, which is an incident angle of the reference beam at the reproducing time suited to reproduce the pattern, on the basis of the difference between the wavelength of the reference beam at the recording time and the wavelength of the reference beam at the reproducing time;   controlling the temperature of the recording medium so that the temperature of the recording medium is generally equal to the aiming temperature; and   controlling the incident angle of the reference beam at the reproducing time so that the incident angle of the reference beam at the reproducing time is generally equal to the aiming incident angle.   
     
     
         2 . An optical information reproducing apparatus comprising:
 an information obtaining device configured to obtain information about a wavelength of a reference beam at recording time from a recording medium which stores main information recorded as a pattern corresponding to interference between an information beam and the reference beam by a main information recording device and information about the wavelength of the reference beam at the recording time recorded by a wavelength information recording device;   a main information reproducing device configured to obtain the main information recorded on the recording medium by applying a reference beam at reproducing time;   a temperature determination device configured to determine an aiming temperature, which is a temperature of the recording medium suited to reproduce the pattern, on the basis of difference between the wavelength of the reference beam at the recording time and the wavelength of the reference beam at the reproducing time;   an incident angle determination device configured to determine an aiming incident angle, which is an incident angle of the reference beam at the reproducing time suited to reproduce the pattern, on the basis of the difference between the wavelength of the reference beam at the recording time and the wavelength of the reference beam at the reproducing time;   a temperature control device configured to control the temperature of the recording medium so that the temperature of the recording medium is generally equal to the aiming temperature; and   an incident angle control device configured to control the incident angle of the reference beam at the reproducing time so that the incident angle of the reference beam at the reproducing time is generally equal to the aiming incident angle.   
     
     
         3 . The apparatus according to  claim 2 , further comprising:
 a wavelength sensing device configured to sense the wavelength of the reference beam at the recording time.   
     
     
         4 . The apparatus according to  claim 2 , further comprising:
 a temperature information recording device configured to record information about the temperature of the recording medium at the recording time on the recording medium.   
     
     
         5 . The apparatus according to  claim 2 , further comprising:
 a wavelength sensing device configured to sense the wavelength of the reference beam at the reproducing time.   
     
     
         6 . The apparatus according to  claim 4 , further comprising:
 a wavelength sensing device configured to sense the wavelength of the reference beam at the reproducing time.   
     
     
         7 . The apparatus according to  claim 2 , further comprising:
 a device configured to obtain information of a reproducing temperature, which is a temperature of the recording medium at the reproducing time,   wherein the temperature determination device determines the aiming temperature by further using the reproducing temperature.   
     
     
         8 . The apparatus according to  claim 4 , further comprising:
 a device configured to obtain information of a reproducing temperature, which is a temperature of the recording medium at the reproducing time,   wherein the temperature determination device determines the aiming temperature by further using the reproducing temperature.   
     
     
         9 . The apparatus according to  claim 5 , further comprising:
 a device configured to obtain information of a reproducing temperature, which is a temperature of the recording medium at the reproducing time,   wherein the temperature determination device determines the aiming temperature by further using the reproducing temperature.   
     
     
         10 . The apparatus according to  claim 7 , wherein the reproducing temperature is subjected to feedback control. 
     
     
         11 . An optical information recording medium with data recorded thereon, the data comprising:
 main information recorded as a pattern corresponding to interference between an information beam and a reference beam; and   information about a wavelength of the reference beam at recording of the main information.   
     
     
         12 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time is recorded in at least one of a lead-in region and a header region of the recording medium. 
     
     
         13 . The medium according to  claim 11 , wherein information about temperature of the recording medium at the recording time is recorded. 
     
     
         14 . The medium according to  claim 12 , wherein information about temperature of the recording medium at the recording time is further recorded in at least one of the lead-in region and the header region of the recording medium. 
     
     
         15 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time of the main information is recorded at lower resolution than the main information. 
     
     
         16 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time of the main information is recorded by angle-multiple recording. 
     
     
         17 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time of the main information is recorded by shift-multiple recording. 
     
     
         18 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time is recorded redundantly at different positions. 
     
     
         19 . The medium according to  claim 11 , wherein the information about the wavelength of the reference beam at the recording time is recorded redundantly at different temperatures. 
     
     
         20 . The medium according to  claim 11 , wherein a recording layer of the optical information recording medium includes a photo polymer.